Method of improving lubricating oil



July 13, 1943. 1, H BRUUN ET AL 2,324,357

METHOD OF IMPROVING LUBRICATING OIL Filed Aug. '7, 1942 Patented July 13, 1943 METHOD OF IMPROVING LUBRICATING OIL .ohannes H. Brunn, Swarthmore, and Gilbert E. Goheen, Prospect Park, Pa., assignors to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Application August 7, 1942, Serial No. 454,039

6 Claims.

This invention relates to a method of treating lubricating oils for the purpose of producing a lubricating oil of improved quality therefrom.

The methods of the present invention possess particular value for treating naphthenic type lubricating oils and the invention will, therefore, be described with particular reference to treating lubricating oil fractions obtained from naphthenic type of crude oils. When naphthenic lubricating oils are treated in accordance with the methods of this invention, certain desirable properties generally associated with lubricating oils obtained from parafnic base crude oils are imparted thereto, particularly the viscosity index of the lubricating oils is substantially improved, and, consequently, the oil is less effected by changes in temperature.

It is well known that lubricating oils, particularly naphthenic type oils, are improved by treatment, at a temperature below the decomposition temperature of the oil, with aluminum chloride. More recent improvements in the process have shown that improved results are obtained, in such relatively low temperature treatment of lubricating oils with aluminum chloride, if an appreciable amount of an alkyl halide is present in the oil during treatment. Such alkyl halides not only enter into an alkylating reaction with the lubricating oil being treated but apparently also serve to activate the aluminum chloride. While the use of alkyl halides with aluminum chloride in relatively low temperature treatment of lubricating oils results in a yield of better oil, the known processes involving their use have the disadvantage of causing the formation of an increased amount of sludge, thereby decreasing the amount of improved treated oil obtained.

The present invention is directed to improvements in the method of treating lubricating oils with alkyl halides in the presence of aluminum chloride or similar Friedel-Crafts agents in order to produce an oil of better quality than has heretofore been produced by processes of this character and, further, to increase the yield of improved treated oil with a corresponding decrease in the amount of sludge formed while, at the same time, employing equivalent or somewhat smaller quantities of both aluminum chloride and alkyl halide than has heretofore been possible in processs of this character.

A diagrammatic outline of a preferred manner of practicing the present invention is illustrated in the single figure of the accompanying sheet of drawings.

In the practice of the present process, the lubricating oil is mixed with lauryl chloride and aluminum chloride in suitable amounts, approximately 0.25 mole of each per mole of oil generally being satisfactory. The materials are thoroughly mixed and slightly heated and the reaction is allowed to proceed at the desired temperature for a suiiicient length of time to effect the desired impro-vement in the oil. After the reaction has continued for the specified time and temperature, preferably with constant agitation, the mixture is allowed to settle into a clear top layer or improved treated lubricating oil and a bottom layer of sludge. The clear treated lubricating oil may then be removed from the sludge, for instance by decantation, and the cil thus obtained is found to have many improved physical properties, particularly a marked improvement in itsviscosity index, and also a greatly improved color.

The principal variables of the process, aside from the oil being treated, are the amounts of reagents used, lauryl chloride and aluminum chloride, and the temperature and time of treatment. These several variable factors are closely related one to another and an increase in the amount of reagents employed, the temperature or the time of treatment will permit a decrease in one or more of the other variables. The net result of subjecting oil to treatment of the present invention remains the same. However, in order to enable the processes of the present invention to be practiced by others, the following ranges, which have been found to be satisfactory, as well as the various factors influencing the selection of the particular conditions to be employed, are given.

In treating naphthenic lubricating oils derived from a mixture of Gulf Coast crude oils, it was found that approximately 0.25 mole of lauryl chloride and aluminum chloride per mole of oil being treated resulted in a satisfactory improvement and yield of treated oil. When smaller amounts of reagents were employed, the time of treatment necessary to eifect a given improvement in the oil was increased; and when greater amounts of reagents were used, while they had no adverse effect either on the quality or quantity of yield, they were apparently of little benefit in proportion to the excess amounts used. The temperature and time of treatment are very closely inter-related. As stated heretofore, the temperature should not be higher than the decomposition temperature of the oil in the presence of aluminum chloride which is generally about 175 to 200 C. At such temperatures, there will be some decomposition of the oil being treated and the reaction proceeds extremely rapidly and is difficult t control, and, therefore, somewhat lower temperatures are preferably used. At 100 C. the reaction is co-mpleted in about 2 hours and at 50 C., approximately 6 hours are required. Temperatures below 50 C. do not appear to be economical, However, the reaction will proceed though extremely slowly at room temperature. Likewise, the character of the oil being treated will eiect the conditions under which the process is practiced. As the oil becomes more paraiiinic in character, the improvements which are obtained become less marked and, consequently, the amount of reagents, the temperature employed and the time of the reaction, which are economical to employ, all decrease.

The use of lauryl chloride in conjunction with aluminum chloride in treatment of lubricating oils has many decided advantages. As stated heretofore, the Vknown pr-ocesses involving the use of alkyl halides in the low temperature treatment of lubricating oils with aluminum chloride, results in a substantial increase in the amount of sludge which is formed and a consequent decrease in the yield of improved treated oil. However, when lauryl chloride is used as the alkyl halide, the yield of improved treated oil is substantially the same as that obtained when a lubricating oil is treated with aluminum chloride alone, without any alkyl halide. It was found that as the number of carbon atoms in the alkyl halide was decreased below twelve, the yield of treated oil also decreased. Similarly, as the number of carbon atoms in the alkyl halide was increased above twelve, the yield of treated oil again declined.

It was found also that when lauryl chloride was used as the alkyl halide with aluminum chloride in the treatment of lubricating oils, the color of the treated oil was improved over the color obtained when aluminum chloride alone, or aluminum chloride and some other alkyl halide, was used for such treatment. The color of the treated oil gradually improved as the number of carbon atoms in the alkyl halide was increased until the maximum improvement was obtained when lauryl chloride was employed as the alkyl halide. Thereafter, as the number of carbon atoms was increased above twelve, the color of the treated oil gradually declined.

It was likewise found that the maximum improvement in the physical properties of the oil, particularly the viscosity index, was obtained when lauryl chloride was used in connection with aluminum chloride in the treatment of lubricating oil. The viscosity index of the treated oil, using chemically equivalent amounts of reagents, alkyl halide and aluminum chloride and analogous conditions, gradually improved as the number of carbon atoms in the alkyl halide was increased until the maximum viscosity index was obtained when lauryl chloride was employed. Thereafter, the Viscosity index of the treated oil gradually declined as the number of carbon atoms in the alkyl halide was increased above twelve.

The improvement in yield, color and viscosity index of the treated oil are not the only advantages obtained by using lauryl chloride in conjunction with aluminum chloride in low temperature treatment of lubricating oils; since, it has also been found that when lauryl chloride is used in the aluminum chloride treatment of lubricating oils, smaller quantities of reagents--aluminum chloride and lauryl chloride-may be employed in order to effect a given amount of improvenient in the oil being treated or, if desired, a shorter time of reaction or a lower temperature of reaction may be employed when lauryl chloride is present in an oil being treated at relatively low temperature with aluminum chloride than is possible when known processes of aluminum chloride treatment of lubricating oils are used.

It should be noted that in the known processes of treating lubricating oils with aluminum chloride, at relatively low temperatures and in the presence of Various alkyl halides, the viscosity and molecular weight of the treated oil which is obtained is somewhat greater than the viscosity and average molecular weight of the oils subjected to the process. When the processes of the present invention, however, are used, it has been found that the treated lubricating oil which is obtained has a somewhat lower viscosity and average molecular weight than the oil charged to the processes. This is an unique advantage and results in the production from naphthenic type lubricating oils of improved lubricating oils having substantially the same boiling range as parainic type lubricating oils of the same viscosity.

In order to better describe the present invention, the following specic example is given, the operation described therein being also diagrammatically described in the single figure of the attached sheet of drawings.

Example 1 A mixture of 300 g. of a Gulf Coast lubricating oil, 48 g. of lauryl chloride (n-dodecyl chloride) and 30 g. of anhydrous aluminum chloride was vigorously stirred for 6 hours at 50 C. After the sludge had been allowed to settle, the oil was decanted, yielding 266 g. Washing of the decanted oil with dilute sulfuric acid, dilute alkali and water in turn, followed by drying, resulted in a yield of 260 g. of very light colored oil.

The residual sludge was treated with dilute acid to decompose the aluminum chloride sludge, the hydrogen chloride produced by this decomposition was removed by blowing steam through the decomposed sludge, and 68 g. black viscous sludge oil was separated from the aluminum hydroxide produced by this decomposition by settling and decantation. This black sludge oil was Washed and dried similarly to the improved lubricating oil. The properties of the oil charged to the process and the oils produced are given in Table 1 below.

While the description of our process has been limited to the use of lauryl chloride, since this is the most readily available lauryl halide, it is apparent that other lauryl halides may be substituted therefor. It will also be apparent that other catalysts of the Friedel-Crafts type may be substituted for aluminum chloride.

We claim:

1. The method of improving lubricating oil Which comprises adding to the oil to be improved a relatively small amount of a lauryl halide and condensing the resulting mixture in the presence of a catalyst of the Friedel-Crafts type.

2. The method of improving lubricating oil which comprises adding to the oil to be improved a relatively small amount of lauryl chloride and condensing the resulting mixture in the presence of aluminum chloride.

3. The method of improving naphthenic lubricating oil which comprises adding to the oil to be improved a relatively small amount of a lauryl halide and condensing the resulting mixture in the presence of a catalyst of the Friedel-Crafts type, the molar ratio of lubricating oil to lauryl halide being substantially 4:1.

4. The method of improving naphthenic lubrieating oil which comprises adding to the oil to be improved a relatively small amount of lauryl chloride and condensing the resulting mixture in the presence of aluminum chloride.

5. The method of improving naphthenic lubricating oil which comprises adding to the oil to be improved a relatively small amount of a lauryl halide and condensing the resulting mixture in the presenceof a catalyst of the Friedel-Crafts type, the molar ratio of lauryl halide to catalyst being substantially 1:1.

6. The method of improving naphthenic lubricating oil which comprises adding to the oil to be improved a relatively small amount of lauryl chloride and condensing the resulting mixture in the presence of aluminum chloride, and the molar ratio of lauryl chloride to aluminum chloride being substantially 1:1.

JOHANNES H. BRUUN. GILBERT E. GOHEEN. 

